1. MULTIPURPOSE Duct flanges are suitable for heating cooling ventilation HVAC systems, and are widely used in air ventilation systems in homes, kitchens, bathrooms, garages, and factories. 2. WHAT YOU GET The package comes with 1 x Duct Connector Flange that Outer Diameter of Top Interface: 235 mm / 9.25 inch; Outer Diameter of Bottom Interface: 248 mm / 9.76 inch; Fit for Ducting Hose with Inner Diameter: 250mm / 10 Inch; Overall Dimensions: 280 x 280 x 80 mm / 11.02 x 11.02 x 3.15 inch (LWH); Diagonal Mounting Hole Distance: 298 mm / 11.73 inch; Adjacent Mounting Holes Distance: 210 mm / 8.27 inch. 3. RELIABLE MATERIAL Made of ABS Plastic, which has good corrosion resistance, temperature resistance and durability. 4. SPECIAL DESIGNED The connector base has screw mounting holes, it can be fixed directly to the wall with screws, which is convenient to use; the ventilation flange has a smooth surface, which is conducive to connecting the air duct.